Plants grow better if there is lots of CO2 around, but devices to make the CO2 burn fuel or gas (link). Only a small fraction of the generated CO2 is actually used. The grower still gains because fuel is so cheap and subsidized anyway, but don't we generate enough CO2 already?

The suggestion is
to take CO2 directly from the air using solar power and concentrate it in the green house. That way the system actually removes CO2 from the air overall. CO2 is taken out of the air by freezing it at night with an absorber refrigerator (link). The refrigerator is recharged with solar energy during the day while the frozen CO2 evaporates and feeds the plants.

Why not use Silicon solar panels and an electric freezer? Could work too, but an absorber refrigerator with a natural day-night cycle fits the application perfectly. Let's leave the Silicon to people who need power during the day.

"when are you gonna come down? When are you going to land? I should have stayed on the farm. I should have listened to my old man."I suspect it's actually carbon monoxide that is the major waste product of power production though. I tried dwarf fruit trees and in my failure I suspect that they need massive amounts of water as well as too much "baby talk" (CO2) to be plausible for the average working man.

[Zimmy] Carbon-monoxide is bad for you because it is very reactive. That same property makes it fairly harmless for the environment. In a mix of air 95% air with 5% CO the CO has a half life of about 5 hours (turns into CO2), so it is gone pretty fast from the environment.

[po] I like to breathe too, but a little extra food is nice. We are not talking about 100% CO2 here, but 1% at most. You can get 20% higher yield with less water and no extra fertilizer (links). Some sources report 70% for selected grains.

Because then you'd be releasing CO2 to the atmosphere, increasing the greenhouse effect. [kbecker] is recycling the CO2, rather than pulling it out from the earth (which is the problem with fossil fuels). It's easy to pull carbon out from underground, hard to put it back.

We shouldnt't want to put it back. That atmospheric carbon eventually turns into plants which feeds animals. The carbon is doing no good, really, being in the ground... The greenhouse effect is not really a "bad" thing. It creates more lush plant growth over the whole planet, which will in turn create more oxygen. Eventually the atmosphere will balance out again. And there will be lots of happy little trees, and happy little squirrels. And let me tell you, there is nothing more delicious than squirrel grilled with onions and peppers... <drool>

Ahh. I missed that distinction. But now I understand. Perhaps [kbecker] could put the hydroponic farm in a giant blimp shaped like a basking shark with a gaping mouth. CO2 would come in the open mouth and be filtered out like nutrious krill, increasing the relative CO2 for the garden within. The sharkblimp design would ensure a constant flow of air from which to harvest to CO2.

[bungston], I think we have to bake this. A blimp with a hydroponic garden that absorbs CO2. It would fly around chimneys of coal firing plants to filter the air. Another fleet would cruise along busy interstates adn autobahns.The project is finaced with fines from companies/countries that violate the Kyoto agreement.